firsy off i would think you should determine what you want to keep? softies,lps, sps? according to anthony calfo you shouldn't mix sps and the others, you are asking for troubles in the battle zone with toxins and so forth, especially in a 30 gal tank which well be pretty close quarters. also if you are wanting sps or even lps you really have to start watching calc.,alk., mag.,and water chem. alot more closely as i have found out then with softies.